Mitochondrial DNA structure of an isolated Tunisian Berber population and its relationship with Mediterranean populations

Abstract

Background: Douiret is an isolated Berber population from South-Eastern Tunisia. The strong geographic and cultural isolation characterising this population might have contributed to remarkable endogamy and consanguinity, which were practiced for several centuries.

Aim: The objective of this study is to evaluate the mitochondrial DNA (mtDNA) genetic structure of Douiret and to compare it to other Mediterranean populations with a special focus on major haplogroup T.

Subjects and methods: Genomic DNA was extracted from blood samples of 58 unrelated individuals collected from the different patrilineal lineages of the population. The hypervariable region 1 of the mtDNA was amplified and sequenced. For comparative analyses, additional HVS1 sequences (n = 4857) were compiled from previous studies.

Results: The maternal background of the studied sample from Douiret was mainly of Eurasian origin (74%) followed by Sub-Saharan (17%) and North African (3%) lineages. Douiret harbours the highest frequency of haplogroup T in the Mediterranean region, assigned to the unique subclade T1a (38%). Phylogenetic analysis showed an outlier position of Douiret at the Mediterranean level.

Conclusions: The genetic structure of Douiret highlights the presence of founders, most likely of Near/Middle Eastern origin, who conquered this area during the Middle/Late Upper Palaeolithic and Neolithic dispersals.

Keywords:

• Douiret
• North Africa
• endogamy
• haplogroup T
• phylogeny

Acknowledgements

The authors thank the three associations: “Association de Sauvegarde de la Nature et de Protection de l’Environnement à Douiret (ASNAPED)”, “Association Twiza pour le Patrimoine, la Solidarité et le Développement” and “Association Tunisienne de la Culture Amazighe” for supporting this research project. They would also like to express their sincere gratitude to Mr Sami Boussetta for his help. They also thank all the volunteers that donated their DNA, making this study possible.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This work was supported by the Tunisian Ministry of Public Health, the Ministry of Higher Education and Scientific Research under Grant [number LR11IPT05] and the European Commission under Grant: [Number: FP7–279171-1, MEDIGENE Project].